Avoiding Chaotin Instability under PID Control of Plythylene Fluidized Bed Reactor (UNIPOL Procees)

https://doi.org/10.22146/ajche.50857

Nayef Mohamed Ghasem(1*), Mohamed Azlan Hussain(2)

(1) Department of chemical Engineering, University of Malaya 50603 Kula Lumpur, Malaysia
(2) Department of chemical Engineering, University of Malaya 50603 Kula Lumpur, Malaysia
(*) Corresponding Author

Abstract


Modeling investigation showed that static and dynamic bifurcation behavior covers wide regions of the design and operatin domain of the fluidized bed reactor for polythylene production. In some cases, if comes across that the optimum static state is unstable and surrounded by a periodic branch with large tempertature oscillations causing fomidably high termperature far above the melting point of the polymer. A proportional-derivative-integral controller has been investigated for the stabilization of these desirableunstable steady states and the characteristic of the closed loop control system are presented and discussed. Even under the PID control scheme it was observed that care should be taken dor selecting suitable control gain to avoid instability.

Keywords


Polyethylene, Fluidized bed, Chaos, Instability, Polymerization

Full Text:

PDF


References

  1. Doedel, E.J., AUTO86: Software for continuation and bifurcation problems in ordinary differential equations , California , Institute of Technology, Pasadena, CA, 1986
  2. Meier, G.B.,Fluidized bed reactor for catalytic olefin polymerization, doctoral thesis, Enschede, The Netherlands (2000).
  3. Gear, C.W.,Numerical initial value problems in ordinary differential equations, Prentice Hall, Englewood Cliffs, New Jersey (1971)
  4. McAuley, K.B., MacGregor, J.F.,Nonlinear product control in industrial gas phase polyethylene reactor, A. I. Ch. E Journal Journal 37 (1991) 825-835.
  5. McAuley, K.B., Macdonald, D.A., McLellan, Effect of operating conditions on stability of gas-phase polyethylene reactors, A I, Ch. E Journal 41 (1995) 868-879.
  6. McAuley, K.M., Talbot, J.P., Hariss, T.J., A comparison of two phase and well mixed models for fluidized bed polyethylene reactors, Chem. Eng. Sci. 49 (1994) 2035-2045
  7. Choi, K.Y., Ray, W.H. The dynamic behavior of fluidized bed reactors for solid catalyzed gas phase olefin polymerization, Chem. Eng. Sci. 40 (1985) 2261-2279.
  8. Dadebo, S.A., Bell, M.L., McLellan, P.J., McAuley, K.B.,Temperature control of industrial gas phase polyethylene reactors Journal of Process Control 7 (1997) 83-95.
  9. Xie, T., McAuley, K.B., Hsu, J.C.C., Bacon, D.W.,Gas phase ethylene polymerization Production processes, polymer properties, and reactor modeling, Ind. Eng. Chem.Res. 33 (1994) 449-479
  10. User Manual, FORTRAN subroutines for mathematics and statistics, Vol. 1, (1985),Dgear 1-10, IMSL Inc. Houston.



DOI: https://doi.org/10.22146/ajche.50857

Article Metrics

Abstract views : 824 | views : 546

Refbacks

  • There are currently no refbacks.


ASEAN Journal of Chemical Engineering  (print ISSN 1655-4418; online ISSN 2655-5409) is published by Chemical Engineering Department, Faculty of Engineering, Universitas Gadjah Mada.